Anybody going to VCF-East have cheap working Oscilloscope/Logic Analyzer to sell?

On Sun, Jul 11, 2004 at 09:20:26PM -0400, Chandra Bajpai wrote: I won't be at VCF-East (and I don't have any surplus test gear), but I do have a couple of recommendations for your PETs... If they come up to the random-character screen (no "*** COMMODORE BASIC ***" banner) or if the RAM reads less than you expect for an 8K machine, the first thing I'd suspect are the sockets, the next thing are the SRAMs themselves. Given how hard it is to find those SRAMs, it might be easier to make a daughter card that fits into the CPU socket that has a JEDEC SRAM socket (for a 6116, 6264, 62256...), and use A15 as a low-true enable to put it below $8000. The first thing, of course, would be to check the board for proper voltages and ripple. High ripple would mostly likely be caused by dry electrolytic caps, given that these machines are ~25 years old. I had an 8K PET once that I sold at least 10 years ago... it was incredibly unreliable... I ended up putting a folded cardboard wedge under the middle of the main board to flex it "just right" so it would come up most of the time. I don't think it was a cold solder joint - I think it just needed new SRAM sockets. Once you do get them working, don't forget that BASIC 1.0 ROMs have problems with the IEEE-488 implementation. I can't recall the nature of the issue, but they don't place nice with most GPIB gear, not even Commodore's own stuff. BASIC 2.0 fixed that. If you are observing disk drive timeouts or lockups, it could be related to that. -ethan -- Ethan Dicks, A-130-S Current South Pole Weather at 12-Jul-2004 01:50 Z South Pole Station PSC 468 Box 400 Temp -89.2 F (-67.3 C) Windchill -129.8 F (-89.90 C) APO AP 96598 Wind 10.5 kts Grid 090 Barometer 675.9 mb (10780. ft) Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html